ItemSubcarrier-Index Modulation for Reed Solomon Encoded OFDM-Based Visible Light Communication(Institute of Electrical and Electronics Engineers Inc., 2019-01-11) Taherkhani, Nima; Kiasaleh, Kamran; 48144648209247532318 (Kiasaleh, K); Taherkhani, Nima; Kiasaleh, KamranIn this paper, we propose the subcarrier-index modulation with Reed Solomon encoded Optical Orthogonal Frequency Division Multiplexing with index modulation (IM-RS-OFDM) scheme for visible light communication (VLC). In this technique, the data is encoded using an RS codeword and then part of the redundancy introduced by the frame which exceeds the clipping range are punctured and their corresponding subcarriers are set as inactive, where the indices of these inactive subcarriers are used to transmit extra information bits. The puncturing of the redundancy aids in mitigating clipping noise generated due to the dynamic range constraints of the optical transmitter by shortening the number of active subcarriers, while the locations of the punctured subcarriers are exploited to convey more bits in order to compensate for the reduction in spectral efficiency caused by coding redundancy. In the proposed scheme, the bipolar transmitting signal is clipped and biased according to DC bias optical OFDM (DCO-OFDM) system, and a Log-Likelihood ratio (LLR) calculation based detector is used to find the indices of punctured symbols in the codeword. Our simulation results show that the new scheme offers a better bit error rate performance compared to the conventional coded OFDM-based visible light communication. © 2019 IEEE. ItemReed Solomon Encoding for the Mitigation of Clipping Noise in OFDM-Based Visible Light Communications(Institute of Electrical and Electronics Engineers Inc.) Taherkhani, Nima; Kiasaleh, Kamran; 48144648209247532318 (Kiasaleh, K); Taherkhani, Nima; Kiasaleh, KamranIn this paper, we present a clipping noise mitigation technique in orthogonal frequency-division multiplexing (OFDM) based visible light communication (VLC) system employing Reed Solomon (RS) coding. In this technique, the data is encoded using an RS codeword and then part of the redundancy introduced by the frame which exceeds the clipping range are removed by applying different number of puncturing, and the redundancy left in the data are used at the receiver side to retrieve the data block. The puncturing of the redundancy aids in mitigating clipping noise generated by truncating the OFDM symbols at the transmitter by shortening the number of active subcarriers, while the residual redundancy are exploited at the receiver for the reconstruction and correction of errors. © 2018 IEEE. ItemReview of Breast Screening: Toward Clinical Realization of Microwave Imaging(Wiley) Modiri, Arezoo; Goudreau, Sally; Rahimi, Asal; Kiasaleh, Kamran; Kiasaleh, KamranMicrowave imaging (MI) technology has come a long way to introduce a noninvasive, inexpensive, fast, convenient, and safe screening tool for clinical breast monitoring. However, there is a niche between the existing understanding of MI by engineers versus clinicians. Our manuscript targets that niche and highlights the state of the art in MI technology compared to the existing breast cancer detection modalities (mammography, ultrasound, molecular imaging, and magnetic resonance). The significance of our review article is in consolidation of up- to-date breast clinician views with the practical needs and engineering challenges of a novel breast screening modality. We summarize breast tissue abnormalities and highlight the benefits as well as potential drawbacks of the MI as a cancer detection methodology. Our goal is to present an article that MI researchers as well as practitioners in the field can use to assess the viability of the MI technology as a competing or complementary modality to the existing means of breast cancer screening. ItemSpatial Beam Tracking for Hermite-Gaussian-Based Free-Space Optical Communications(SPIE) Kiasaleh, Kamran; 48144648209247532318 (Kiasaleh, K); Kiasaleh, KamranThe problem of spatial tracking for Hermite-Gaussian free-space optical (HG-FSO) links is addressed. Since HG waveforms allow for the simultaneous presence of orthogonal spatial channels, FSO-HG has the potential of offering a considerable increase in system capacity as compared with the standard FSO systems. To harness this capacity gain, the problem of spatial tracking becomes of paramount importance as the presence of spatial error significantly impacts the orthogonality of the HG waveforms. We, then, consider spatial tracking using a standard quad-detector arrangement and assume that the background noise and/or receiver thermal noise are large enough to warrant a Gaussian detection statistics. The performance is assessed in terms of the probability density function of the spatial tracking error for HG order of up to 3. In assessing performance, it is assumed that the impact of the cross-talk among the spatial modes is negligible under the steady-state condition. Numerical results are presented to assess the viability of the tracking loop. Numerical results show that among the HG waveforms with orders ranging from 1 to 3, the second-order HG waveform offers the best tracking performance and, hence, must be selected for the purpose of tracking in HG-FSO systems.